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40ff484d | 1 | /* Formatted output to strings. |
f0007cad | 2 | Copyright (C) 2004, 2006-2012 Free Software Foundation, Inc. |
40ff484d LC |
3 | Written by Simon Josefsson and Paul Eggert. |
4 | ||
5 | This program is free software; you can redistribute it and/or modify | |
6 | it under the terms of the GNU Lesser General Public License as published by | |
7 | the Free Software Foundation; either version 2, or (at your option) | |
8 | any later version. | |
9 | ||
10 | This program is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | GNU Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public License along | |
16 | with this program; if not, write to the Free Software Foundation, | |
17 | Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ | |
18 | ||
19 | #include <config.h> | |
20 | ||
21 | /* Specification. */ | |
22 | #include <stdio.h> | |
23 | ||
24 | #include <errno.h> | |
25 | #include <limits.h> | |
26 | #include <stdarg.h> | |
27 | #include <stdlib.h> | |
28 | #include <string.h> | |
29 | ||
30 | #include "vasnprintf.h" | |
31 | ||
32 | /* Print formatted output to string STR. Similar to sprintf, but | |
33 | additional length SIZE limit how much is written into STR. Returns | |
34 | string length of formatted string (which may be larger than SIZE). | |
35 | STR may be NULL, in which case nothing will be written. On error, | |
36 | return a negative value. */ | |
37 | int | |
38 | snprintf (char *str, size_t size, const char *format, ...) | |
39 | { | |
40 | char *output; | |
41 | size_t len; | |
42 | size_t lenbuf = size; | |
43 | va_list args; | |
44 | ||
45 | va_start (args, format); | |
46 | output = vasnprintf (str, &lenbuf, format, args); | |
47 | len = lenbuf; | |
48 | va_end (args); | |
49 | ||
50 | if (!output) | |
51 | return -1; | |
52 | ||
53 | if (output != str) | |
54 | { | |
55 | if (size) | |
56 | { | |
57 | size_t pruned_len = (len < size ? len : size - 1); | |
58 | memcpy (str, output, pruned_len); | |
59 | str[pruned_len] = '\0'; | |
60 | } | |
61 | ||
62 | free (output); | |
63 | } | |
64 | ||
65 | if (INT_MAX < len) | |
66 | { | |
67 | errno = EOVERFLOW; | |
68 | return -1; | |
69 | } | |
70 | ||
71 | return len; | |
72 | } |